Compressor



I Feb. 3; 1959 I A. RYBA, 2,872,102

' COMPRESSOR Filed Dec. 19, 1956 IN V EN TOR.

United States COMPRESSOR Anton Ryba, Bolzano, Italy, assignor to Stempel-Hermetik G. in. b. H., Frankfurt am Main, Germany Application December 19, 1956, Serial No. 628 536 Claims priority, application Austria December 19, 1955 7 Claims. (Cl. 23055) The present invention relates to compressors.

More particularly, the present invention relates to electromagnetic compressors wherein a piston, for example of a compressor is connected to an oscillating armature for oscillation therewith.

In conventional compressors of this type, in order to prevent a part of the moving mass from striking against a part of the compressor at the end of a stroke thereof, thedirection of the lines of magnetic force which move the armature is chosen so as to be different from the direction in which the armature moves, or the air gap in which the armature oscillates is made considerably greater than the usable stroke of the piston. As a result, the

conventional structures require a great amount of conductive copper, a large exciting current, and all of the disadvantages resulting from these features, in particular poor efliciency and the necessity of using a large amount of material.

One of the objects of the present invention is to provide a compressor of the above type which overcomes the above drawbacks and in which the lines of force which move the armature extend in the direction of armature movement.

Another object of the present invention is to provide a vcompressor of the above type which overcomes the above drawbacks without causing a part of the moving mass to strike against a part of the compressor at the end of a stroke thereof.

It is also an object of the present invention to provide a compressor capable of accomplishing the above objects and at the same time composed of simple and ruggedly constructed elements which are very reliable in operation.

With the above objects in view the present invention mainly consists of an electromagnetic compressor which includes an armature and an annular coil. A yoke means is distributed along and extends about the coil and has an inner portion directed toward the axis of the coil and formed with a free space in Which the armature is movable in a direction parallel to the axis of the coil, the magnetic lines of force which move the armature extending substantially in the direction of movement of the armature. This armature may be connected to a compressor element such as a piston for actuating the latter.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a sectional elevational view of a compressor according to the present invention, the section of Fig. 1 being taken along line AA' of Fig. 2;

Fig. 2 is a fragmentary, sectional plan view of the compressor of Fig. 1 taken along line BB' of Fig. l; and

Fig. 3 is a fragmentary sectional elevational view of a different embodiment having inclined pole faces.

2,872,102 Patented Feb. 3, 1959 The compressor which is illustrated in Figs. 1 and 2 includes a housing 1 which is open at the top and which has a transverse bottom wall and an endless side wall which may be circular, the housing 1 being made of any suitable substantially rigid material which is resistant to pressure. The open end of the housing 1 is closed by a cover 2 which rests upon an inner annular flange rigid with the side wall of the housing 1. This side wall is also formed with an inner annular groove which receives a snap ring 3 which maintains the cover in its closing position on the inner flange of the housing 1. The cover 2 is made of a nonmagnetic material.

Within the housing 1 is located an electromagnet means which includes the yoke means 4, 5 and the annular coil 6; This yoke means is made up of a plurality of U-shaped yoke members 4. Each of the yoke members 4 is composed of a group of laminations, and the several groups of laminations are distributed about the axis of the coil 6 with the inner and outer legs of each yoke member extending parallel to this axis and with the bottom transverse portion which interconnects the legs of each yoke member extending radially with respect to the coil axis. The coil is received in the spaces between the legs of the yoke members 4. The yoke means is completed by the return pole pieces 5 which are also distributed radially with respect to the coil axis. These return pole pieces 5 respectively overlap the free end portions of the outer legs of the yoke members 4 and extend from these outer legs toward the coil axis.

The yoke means is formed at an inner portion directed toward the coil axis with a free space in which an armature '7 may oscillate in a direction parallel to the coil axis. This free space is formed in part by the inner end faces of the return pole pieces 5, these inner end faces being directed toward the coil axis and being located at a greater distance from this axis than the inner faces of the inner legs of the yoke members'4, since the return pole pieces 5 terminate short of the latter inner faces which are directed toward the coil axis. The inner legs of the yoke members 4 also terminate short of the return pole pieces 5, so that the inner ends of the latter and the free ends of the inner legs of the yoke members 4 define a free annular space in which the annular armature '7 is movable in a direction parallel to the coil axis.

All of the groups of laminations of the electromagnet means which constitute the yoke members 4 together with the coil 6 are advantageously embedded in an insulating mass which hardens while it cools and solidifies. The return pole pieces 5 are similarly embedded in a similar insulating mass in the form of a ring carrying the pole pieces 5.

The annular armature the space formed between the inner ends of the return pole pieces 5 and the upper ends of the inner legs of the yoke members 4 is made of a ferromagnetic material and is fixed to an inner annular member 8 of nonmagnetic material which is in turn fixed to the piston 9. For example, the member 8, which forms a means for interconnecting the armature 7 and the piston 9, may be poured into a suitable mold which cooperates with the armature 7 to cause the material of the member 8 to surround an inner annular projection of the armature '7 so that this projection becomes embedded in member 8 when the latter solidifies, and a bore of the member 8 may be provided with threads which cooperate with outer threads at the upper portion of the piston 9 to fix the latter to the member 8.

A spring means is provided for connecting the assembly composed of elements 79 with the housing, and this spring means includes the springs 10 and 11 located within the piston 9 and respectively pressing against the upper and lower faces of a flange of a member 12,

7 which is freely movable in which a cylinder 13 is formed, so that the cylinder 13 is an integral part of the housing, and the piston 9 slides in. this cylinder. The housing 1 is also formed at its lower face with an annular groove 16' coaxially surrounding the cylinder 13 toprovide the latter with a bottom annular face, and the cylinder 13 is traversed at its bottom end by a plate 14 which presses against the bottom annular face of the cylinder 13 and which forms a pressure valve for the compressor. A relatively small leaf spring 15 is carried by the bottom cover 18 of the housing and presses against the plate 14 for urging the latter to its closed position where it closes the bottom end of the cylinder 13. A pressure conduit 16 through which the compressed fluid flows to a desired location communicates through a lower portion of the housing 1 with the annular groove 16'. The bottom end of the housing 1 is provided with threaded bores which receive the screws 17 which maintain the cover 18 in its closed position. The suction conduit 19 is connected to the cover 2 and communicates through the latter with the interior of the piston 9, and the fluid which is to be compressed passes through the conduit 19 into the cylinder 9. The head end of the cylinder 9 is formed with a plurality of openings arranged in a circle and covered at the bottom face of the piston 9 by springy fingers of a springy plate 20 fixed to the bottom face of the piston 9 and cooperating with the openings in the head end thereof to form suction valves in which the fluid flows into the cylinder 13 ahead of the piston 9 during the suction strokes of the latter.

The leads 21 for connecting the coil 6 to a source of current pass through suitable bores of the housing 1. Also, the housing 1 is formed with cooling fins 22 for leading away heat which develops during operation of the compressor.

The above described compressor operates as follows:

The coil 6 is connected to a source of single phase currerit,-='andthe coil 6 is also connected in series with a rectifier so that only half waves flow through the coil 6 in order to excite the latter periodically so as to set the mass 79 into oscillation. The magnetic force pulls the armature 7 downwardly, as viewed in Fig. l, and this movement results in the pressure stroke of the compressor, the suction valves 20 being closed at this time.

When the fluid in cylinder 13 ahead of piston 29 is compressed to a given degree the plate 14 automatically moves against the force of spring 15 away from the cylinder 13 so that the compressed fluid flows to the groove 16 and from the latter through the conduit 16 to a desired location.

During the return or suction stroke of the piston 9, fluid flows through the conduit 19, the interior of the piston 9, and the suction valve 20 into the chamber ahead of piston 9. The springs 10 and 11 cooperate with the mass 79 to cause the latter to oscillate substantially at the frequency of the exciting current. It is of advantage to construct at least the spring 10 in a manner which causes its convolutions to engage each other in order to limit the pressure stroke of the piston.

It will be noted that with the above described structure the magnetic lines of force which move the armature 7 downwardly, as viewed in Fig. 1, during the pressure stroke of the compressor, extends substantially in the direction of movement of the armature. However, no part of the moving mass will strike against another part of the compressor because the convolutions of the spring 10 engage each other to limit the stroke of the piston and prevent such undesirable striking of elements against each other.

The housing 1 is formed with concentric annular lubricant reservoirs 23 and 24 which communicate with each other and with the outer face of piston 9 which engages cylinder 13 through a bore 25 formed in the housing 1, so that in this way the piston 9 is lubricated.

Fig. 3 shows a construction identical with that described above except that the armature 27, which otherwise is identical with the armature 7, is provided with a lower frusto-conical face which is directed toward and inclined in the same direction as the free ends 26 of the inner legs of the yoke members, these free ends 26 also forming part of a frusto-cone whose axis coincides with that of the coil 6. Except for the frusto-conical pole faces of the armature and yoke members, the embodiment of Fig. 3 is identical with that of Figs. 1 and 2. These pole faces are of advantage with respect to magnetic dispersion.

The invention is not limited to the details of the above described structure which illustrates the invention only by way of example. For example, the return pole pieces 5 may be replaced by a plate of sintered material, a sep arate cylinder may be pressed into a bore of the housing 1 to receive the piston, and the compressor itself may take any shape and may be rectangular, for example, as will be the case when only a pair of opposed groups of laminations are used in the electromagnet means.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of compressors differing from the types described above.

While the invention has been illustrated and described as embodied in electromagnetic compressors, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an electromagnetic compressor, in combination, an armature; an annular coil; yoke means distributed along and extending almost completely around said coil and having at an inner portion directed toward and located nearer to the axis of said coil than the remainder of said yoke means a pair of spaced end faces respectively directed toward a pair of different surfaces of said armature and defining between themselves part of a free space in which said armature is movable in a direction parallel to said axis, the magnetic lines of force which move said armature extending substantially in the direction of movement of said armature, whereby said armature may be connected to a compressor element such as a piston for actuating the latter.

2. In an elecromagnetic compressor as recited in claim 1, said free space being located at one end of said inner portion of said yoke means.

3. In an electromagnetic compressor, in combination, a plurality of substantially U-shaped yokes distributed about a predetermined axis and each having inner and outer legs parallel to said axis, said legs of each yoke respectively having free end portions and respectively having opposite end portions interconnected by a transverse yoke portion which extends radially with respect to said axis; an annular coil located in the space between the legs of said yokes; a plurality of return pole pieces distributed about and extending radially with respect to said axis, said return pole pieces respectively overlapping the free end portions of said outer legs of said yokes, extending from said outer legs toward said axis, and terminating short of the inner faces of said inner legs of said yokes which are directed toward said axis, said inner legs of said yokes respectively terminating short of said return pole pieces, whereby a free space is formed between the inner end faces of said return pole pieces which are directed toward said axis and the free end portions of said inner legs of said yokes; and an armature freely movable in said free space in a direction parallel to said axis, whereby the lines of magnetic force which move said armature extend substantially in the direction in which said armature moves.

4. In an electromagnetic compressor, in combination, an armature; an annular coil; yoke means distributed along and extending almost completely around said coil and having at an inner portion directed toward and located nearer to the axis of said coil than the remainder of said yoke means a pair of spaced end faces respectively directed toward a pair of different surfaces of said arma ture and defining between themselves part of a free space in "which said armature is movable in a direction parallel to said axis, the magnetic lines of force which move said armature extending substantially in the direction of movement of said armature; a housing carrying said yoke means; a piston having an axis substantially coinciding with that of said coil; means interconnecting said piston with said armature for rendering said armature and piston movable together; and spring means located partly within said piston and interconnecting the assembly formed by said piston, armature, and interconnecting means with said housing.

5. In an electromagnetic compressor as recited in claim 4, said spring means including an element. located in said piston and against which a spring of said spring means presses.

6. In an electromagnetic compressor as recited in claim 1, said free space being defined in part by a portion of said yoke means which forms part of a frusto cone having an axis substantially coinciding with that of said coil and said armature having a frusto-conical surface directed toward and inclined in the same direction as said portion of said yoke means.

7. In an electromagnetic compressor as recited in claim 4, a cylinder carried by said housing and in 'which said piston slides, said housing being formed with an annular lubricant reservoir surrounding said cylinder and communicating through suitable passage means with the surface of said piston which engages said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 2,054,097 Replogle Sept. 15, 1936 2,258,586 Glassing Oct. 14, 1941 2,659,310 Ryba Nov. 17, 1953 2,630,760 I Ryba Mar. 10, 1953 FOREIGN PATENTS 262,884 Switzerland Oct. 17, 1949 

